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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.oracle.svm.core.option;

import java.util.List;
import java.util.function.Consumer;

import org.graalvm.nativeimage.ImageSingletons;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;

import com.oracle.svm.core.feature.AutomaticallyRegisteredImageSingleton;
import com.oracle.svm.core.util.ImageHeapList;

import jdk.graal.compiler.api.replacements.Fold;
import com.oracle.svm.core.traits.BuiltinTraits.AllAccess;
import com.oracle.svm.core.traits.BuiltinTraits.SingleLayer;
import com.oracle.svm.core.traits.SingletonLayeredInstallationKind.InitialLayerOnly;
import com.oracle.svm.core.traits.SingletonTraits;

/**
 * Allows to register commands for validating runtime options at run time.
 */
@AutomaticallyRegisteredImageSingleton
@SingletonTraits(access = AllAccess.class, layeredCallbacks = SingleLayer.class, layeredInstallationKind = InitialLayerOnly.class)
public class RuntimeOptionValidationSupport {
    @SuppressWarnings("unchecked")//
    private final List<RuntimeOptionValidation<?>> validations = (List<RuntimeOptionValidation<?>>) ImageHeapList.createGeneric(RuntimeOptionValidation.class);

    @Platforms(Platform.HOSTED_ONLY.class)
    public RuntimeOptionValidationSupport() {
    }

    @Fold
    public static RuntimeOptionValidationSupport singleton() {
        return ImageSingletons.lookup(RuntimeOptionValidationSupport.class);
    }

    @Platforms(Platform.HOSTED_ONLY.class)
    public synchronized void register(RuntimeOptionValidation<?> validation) {
        assert validation != null;
        validations.add(validation);
    }

    public void validate() {
        for (RuntimeOptionValidation<?> validation : validations) {
            validation.validate();
        }
    }

    public static class RuntimeOptionValidation<T> {
        private final Consumer<RuntimeOptionKey<T>> validation;
        private final RuntimeOptionKey<T> optionKey;

        public RuntimeOptionValidation(Consumer<RuntimeOptionKey<T>> validation, RuntimeOptionKey<T> optionKey) {
            this.validation = validation;
            this.optionKey = optionKey;
        }

        void validate() {
            validation.accept(optionKey);
        }
    }
}
